A049687 - OEIS

A049687 as a triangular array

0

1 1

1 3 1

1 4 4 1

1 5 5 5 1

1 6 7 7 6 1

1 7 8 9 8 7 1

1 8 10 11 11 10 8 1

1 9 11 14 13 14 11 9 1

1 10 13 15 17 17 15 13 10 1

1 11 14 18 18 21 18 18 14 11 1

1 12 16 20 22 23 23 22 20 16 12 1

1 13 17 22 24

0 1 1 1 1 1 1 1 1 1 1 1 1

1 3 4 5 6 7 8 9 10 11 12 13

1 4 5 7 8 10 11 13 14 16 17

1 5 7 9 11 14 15 18 20 22

1 6 8 11 13 17 18 22 24

1 7 10 14 17 21 23

1 8 11 15 18 23

1 9 13 18 22

1 10 14 20

1 11 16

1 12

1